• Elastomers and Composites
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• v.35 no.3
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• pp.227-235
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• 2000

This study focused on the recycling technology and application of waste polyurethane scrap($5{\sim}7mm$) and waste urethane form from the footware scrap. Firstly we suggest the waste polyurethane can be used as a component of medium for hydroponic rose culture. Secondly, recycled thermoplastic polyurethane(RTPU) was produced and blended it with high impact polystyrene(HIPS). And also, in order to extend application of recycling field, the former was produced with adding the amine foaming agent to RTPU/HIPS alloy. The main purpose of this study is to diverse of the recycling of the waste polyurethane.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.141-144
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• 2000

Highly open porous polymer matrices are required for high density cell seeding, efficient nutrient, and oxygen supply to the cells cultured in the three dimensional matrices. However, there are severe problems of mass transfer limitations within the cell/scaffolds culture system. Thus we hypothesize that continuos-flow culture conditioning of cells with the scaffolds may improve the cell viability and the differentiated function. In this study, we fabricated porous PLGA scaffolds by using gas-foaming/salt-leaching method as previous described. Viscous PLGA gel paste contains ammonium bicarbonate particulates, acting as a gas-foaming agent as well as a salt-leaching porogen, were cast into Teflon mold and dried. Ammonium bicarbonate salt upon contact to an acidic aqueous solution evloves gaseous ammonia and carbon dioxide by itself. And we conjugated galactose moiety [AGA; $N-(aminobuty1)-O-{\beta}-D-galactopyranosyl-(1{\rightarrow}4)-D-glucoamide]$ to the terminal end group of a PLGA to increase the cell adhesion and matain the differentiated function of hepatocytes. Cell-seeded scaffolds were secured in a flow bioreactor chamber and exposed to continuous flow at 5 ml/min. As a result of our study, the high yield of hepatocytes attachment was accomplished by increasing the concentration of PLGA-AGA conjugate in polymer scaffolds and cells in the scaffolds under continuos flow condition maintained a high level of viability and albumin secretion rate of cultured hepatocytes showed a higher level that of control groups.

• Polymer(Korea)
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• v.25 no.5
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• pp.707-718
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• 2001

Polypropylene (PP) exhibits many beneficial properties such as low density high thermal stability, chemical resistance, good processability and recyclability. However, only limited research has been done on expanded polypropylene (EPP). In this study, we were trying to prepare EPP with chemical blowing agent. Ethylene-octene copolymer (mPE) was melt blended with PP to enhance melt fluidity of PP at processing temperature and to make more flexible foamed material. Prior to foaming, phase morphology of PP/mPE blends were investigated to examine the effect of phase morphology on the foaming ratio and cell structure of foams. Phase morphology of PP/mPE blends were affected by the content of mPE and mixing torque ratio. At the same composition, it was affected by mixing rpm. High blowing ratio and stable cell structure were obtained in the blend which has the continuous PP matrix with dispersed droplets of mPE.

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.71-77
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• 1997

Low foaming acidic degreasing agent(LFADAs) were prepared by blending sorbitol, n-octanoic acid, MJU-100A, Tetronix T-701, Na-dioctyl sulfosuccinate, Demol C, and phosphoric acid. The physical properties of LFADAs tested with aluminum specimen showed the following results ; when 3wt% LFADA-6 was performed at $70^{\circ}C$, the degreasing rate was 95% which is comparitively good, and the percentage of etching was 0.275% which was found to be less than that of commercialized product. When 20wt% of LFADA-6 was added at $65^{\circ}C$, the percentage of derusting was 92% and the good defoaming effect proved by following low foaming power tests respectively : Ross and Miles, and Ross and Clark methods.

• Composites Research
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• v.31 no.4
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• pp.133-138
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• 2018

Polymer foams were used to fill the void in the structure in addition to flame retardant and heat insulation. Polymer foams such as polyurethane, polyisocyanurate, poly(vinyl chloride), polyethylene terephthalate were used to weight lighting materials. In this study, epoxy foam was used to improve mechanical properties of polymer foam. Acid anhydride type hardener reacts with polyol. Using this phenomenon, if blowing agent was added into epoxy resin using acid anhydride type hardener, formation and compressive properties of epoxy foam was studied. Formation of polymer foam was compared with type of blowing agent and concentration of blowing agent via compressive test. As these results, optimized condition of epoxy foam was found and epoxy foam had better compressive property than other polymer foam.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.289-292
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• 2001

Aluminium foams, having a closed cell structure, fabricated by applying the powder compact method and an induction heating were studied. The powdered A6061 mixed with the powdered titanium hydride as a foaming agent was hot pressed into a foamable precursor. The resulting precursor was foamed by induction heating up to desired temperature. The effects of the titanium hydride content ($0.3{\~}1.5 wt.\%$), pressing pressure of the foamable precursor material (50-150kN), the forming temperature ($610{\~}690^{\circ}C$) and heating rate during foaming on the expansion behavior of the foam were investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.253-259
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• 1996

The purpose of this study is to investigate the fundamental properties of polyurethan concrete. Polyurethane must be expanded by means of a blowing agent during polymerization. Chemical blowing is caused by the reaction water with isocyanate. Binder system for polyurethane concrete is based on polyol and isocyanate with catalyst, surfactant, and methyl chloride. Polyurethane concretes are prepared with various grading of aggregate, and tested for compressive, flexural strengths, flow test, foaming multiple proportion, working life, condition of surface, distirbution of aggregate. From the test results, the foaming of polyurethane concretes are affceted by amount and grading of aggregate. Workability increases with raising amount of methy chloride and working life reduced according to amount of catalyst. The mix proportion of B with methyl chloride of 1% and catalyst of 0.1g for polyurethane concrete is recommended in consideration of strengths, condition of surface and balance between cost and performance.

• Macromolecular Research
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• v.16 no.3
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• pp.218-223
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• 2008

In order to obtain crosslinked poly(butylene succinate) (PBS) foams with a closed-cell structure, a commercial-grade PBS was first modified in the melt using two different branching agents to increase the melt viscosity. The rheological properties of the branched and crosslinked PBS were examined by varying the amount of the branching agents. The complex viscosity of the crosslinked PBS increased with increasing amount of the branching agent. However, it decreased with increasing frequency. When 2 phr of the branching agent was added to PBS, the storage modulus (G') was higher than the loss modulus (G") throughout the entire frequency range, showing that the addition of a branching agent increases the melt viscosity and elasticity of PBS effectively. Closed-cell PBS foams were prepared by mixing the chemical blowing agent with the crosslinked PBS. The effect of the foaming conditions such as temperature and time, and the amount of the crosslinking agent on the structure of the expanded PBS foams were also investigated.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.760-767
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• 2005

The goal of this study was to find an application method of the waste soda-lime glass as the feed material for foamed glass by foaming of hydrated waste glass. The proper conditions for the foaming of hydrated waste glass were found to be: temperature of $92.5^{\circ}C$; reaction time of 10~20 min; particle size of -325 mesh as the unhydrated glass starting materials; and graphite weight to the hydrated glass ratio of 0.003 as the foaming agent. The resulting formed glass made from hydrated mixed waste glass under above mentioned conditions had the characteristics of density less than $0.2g/cm^3$ and thermal conductivity of $0.05kcal/mh^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.39 no.4
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• pp.488-498
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• 2022

The effects of 1,3-Butanediol, 1,2-Pentanediol, and 1,2-Hexanediol in surfactant solutions on cmc, surface tension, foaming and emulsifying properties were determined. The addition of diols in aqueous surfactant solution decreased cmc and surface tension, and enhanced the foaming and emulsifying power. This trend is more significant by the longer hydrocarbon chain length of the diols. This property was confirmed because the diol's alkyl chain and the hydrophobic interaction with the surfactant reduce the cohesive force of water and increase the interaction between the head groups of the surfactant at interface. In addition, MIC test was conducted to determine the preservative power of each diol, and as a result, the antibacterial activity was effective in the order of 1,2-HDO > 1,2-PDO > 1,3-BDO. The results of this study show that diol can be applied to cosmetics as an auxiliary surfactant and antibacterial agent.